It is desirable in the setting of agricultural field treatment to provide multiple supplements to the soil. Supplements may include fertilizers such as nitrogen, phosphorus, and potassium, pH balancing factors such as lime, and various chemicals, including herbicides and pesticides. It is known to provide agricultural material spreaders with a plurality of bins to allow operators to selectively release one or more materials, or to selectively release a carefully determined mixture of materials, from a spreader during a single pass through a field. This known method allows the operator to limit unnecessary and unproductive travel to and from fields, excess loading and unloading of bins, and excess passes through fields. Fuel expense, invested time, and vehicle wear and tear are all substantial costs associated with spreading materials. Therefore, it is highly desirable to achieve material spreading while limiting these costs. The present invention is an improvement over the existing technologies. The present invention maximizes applicators"" ability to extract multiple functions from a single piece of equipment, thereby minimizing investment and allowing equipment configuration modifications to enhance efficiency.
Prior patents that disclose technology related to plural bin material spreaders relate to xe2x80x9cprecision farming,xe2x80x9d a practice that includes the collection of detailed information about soil types at various locations in a field and the calculation and application of appropriate materials to those locations by a spreader coupled to a location sensor. Examples of such patents include U.S. Pat. Nos. 4,630,773 and Re. 35,100. The ""773 patent discloses a spreader having plural bulk material holding compartments or bins, each with an associated metering device for the release of material onto a single conveyor for conveyance to a spreading device, such as a spinner. This structure is disclosed as being coupled with a positioning, mapping, and control system. Such a configuration does not allow conversion to single bin use, as may be desired for application of lime. Further, the metering devices of the ""773 patent do not readily accommodate materials that tend to bind, such as lime, or that display poor flowability characteristics.
Other known art relates to plural bin material spreaders having multiple conveyors. Examples include U.S. Pat. Nos. 5,950,933, and 5,052,627. The ""933 patent discloses a dual bin, stacked conveyor arrangement within a major compartment wherein the major compartment is subdivided by a movable wall to form a secondary compartment of selectable dimensions. The ""627 patent discloses parallel conveyors within a major compartment and a supplemental, exterior compartment for the release and entrainment of a minor component into a conveyed material stream.
The prior art fails to disclose a convertible system convenient for use as a single or converted plural bin spreader or for use with materials having dramatically different flowability characteristics. A convertible system is desirable because in given fields, some materials are applied at much higher rates than other materialsxe2x80x94sufficiently higher rates to demand a dedicated spreader having full bin capacity available for one material or one material mix. In such applications, use of primary bin volume to house a secondary bin, walls, or conveyor is wasteful, and necessarily limiting to the single material load size. Further, some materials (such as lime, or in the alternative setting of roadway deicing, salt and sand) tend to clump or form concrete-like masses that may clog machinery. Such materials are preferably carried and dispensed with a minimum of structural components that may promote clogging. Given these material characteristics and varying application rate demands, there is a definite need for a material spreader having the capability to serve at times as a simple conveyor for a single batch of bulk materials without excess machinery and obstacles that may be subject to clogging. There is a further need to provide such a spreader that is convertible for use as a plural-bin applicator. Such convertibility may decrease overall equipment costs for operators to the extent that it allows for convenient conversion and consolidation of functions into one functionally adaptable machine rather than multiple machines.
Prior art machines fail to provide this convertibility. For example, the device of the ""773 patent is limited to application with materials that will not clump or clog in the metering wheels. Further, the ""773 patent fails to disclosexe2x80x94or to suggestxe2x80x94the need to provide for convertibility between a simple single bin and conveyor spreader and a multiple bin design.
There is similarly a need for a convertible plural bin and conveyor material spreader in the field of roadway materials application. For the majority of surfaces that may require chemical, salt, or sand treatment to increase friction and reduce freezing temperature, traditional materials, such as bulk, inexpensive road salt, may be used. This relatively inexpensive material has the disadvantage of being highly corrosive and, therefore, being undesirable for application to bridges, overpasses, and other selected structures or surfaces that are highly reinforced by materials subject to corrosion, such as iron or steel within concrete. For such structures or surfaces, a more expensive, less corrosive deicer is often specified. An example of such a deicer is Calcium Magnesium Acetate (CMA). Due to a dramatic difference in cost between traditional roadway salt and CMA, it is necessary to limit the application of CMA to only those areas where the presence of, and need to protect, reinforcing steel demands such use. Therefore, it has been necessary to use separate trucks for the transport and application of CMA and traditional materials application. It has further been necessary for CMA-carrying trucks to cover many miles without releasing material during travel as the truck moves between sensitive bridges, overpasses, etc. There is, therefore, a need for a material spreader that will accommodate the transport and selective application of bulk and custom application materials from a single unit. There is a further need for such a spreader that is convertible between simple, single bin use and the plural bin use identified herein as advantageous. Finally, there is a need for such a spreader wherein conveyance and spreading means may accommodate materials of a nature that bind or tend to form conglomerations when exposed to environmental conditions.
In roadway applications, the dual goals of providing traction (primarily via the application of sand) and reducing the freezing temperature (primarily via the application of salt) vary in importance depending on numerous factors (e.g. incline, curve embankments, traffic volumes, anticipated temperatures, etc.). Historically, operators would pre-mix components, such as salt and sand, to load a vehicle for application to a variety of road surfaces. This necessarily entailed labor to create the mix (via skid loaders or other equipment). Further, it necessarily resulted in too much salt or sand on some surfaces and too little salt or sand on other surfaces. Therefore, there has been and remains a need for a system that eliminates the need to premix components in a fixed ratio and provide for on-the-fly adjustment of salt-to-sand ratios for application to various targets that will be encountered, such as ramps, intersections, curved road sections and straight road sections.
Whether in the field of agriculture, road or pavement deicing, or other applications, convertibility allows farmers, companies, and state and local governments to maximize the functionality of their fleets. At times of shrinking budgets, the ability to derive multiple uses from a single piece of equipment or from a single platform presents tremendous cost savings. Dump body vehicles need to be usable for earth moving, debris removal, salt or sand spreading, and, as disclosed above, plural materials spreading. Highway Equipment Company has previously demonstrated the commercial advantages of convertible equipment, and the present invention is a further improvement in convertible equipment technologies. Through convertibility, a fleet can achieve year-round use, minimize equipment dormant periods, and minimize the number of vehicles that need to be purchased.
The present invention is a convertible materials applicator having a secondary bin and conveyance means insert. The plural bin functionality may be imparted through a variety of insert walls. In a preferred embodiment, a primary bin or compartment having a centrally located belt-type conveyor positioned generally along the center of the bottom wall of the bin is adapted to receive an insert secondary bin and conveyor. Operation of the dual conveyor configuration allows simple and convenient control of materials release from plural bins without the infirmity of substantial delays as may be caused when a product mix is placed on a conveyor by metering devices remote from the point of spreading and when the application of that mix by the spreader is delayed to allow transport of a desired mix via the conveyance means to the spinner or other spreading or release device. Rather, the dual conveyors provide a spreader with a controllable release of a desired mix through manipulation of individual product streams by manipulation of conveyor or conveyance means speed. In single bin operation, without the inserts or walls installed, the present invention may serve as a traditional, simple bulk material spreader with maximum materials-carrying capacity unhindered by fixed, interior walls. The following description and drawings are directed primarily towards stand-alone units that an operator may mount on a vehicle or trailer. However, it will be understood by those skilled in the art upon learning the presently disclosed technology that the present invention encompasses convertible plural bin and conveyor spreaders that are dedicated spreading vehicles, insert devices for dump bodies, or multipurpose dump body vehicles wherein the primary bin may be raised to effect material dumping in addition to a controlled conveyance means for transport of material to be released.